Abstract

Theoretical simulation and experiments based on a prism beam expander and an echelle
grating are conducted to study the dependence of linewidth and pulse energy on incidence angle and
slit width. With a larger prism incident angle or narrower slit width, the linewidth becomes
narrower while the laser pulse energy becomes lower. However, the pulse energy can be improved by
optimally designing the prism beam expander. In addition, a subpicometer linewidth ArF laser is
obtained with a double-prism beam expander and an echelle grating.